Automatic contour shaping fixture



31, 193. B. D. BROWN y fi AUTOMATIC CONTOUR SHAPING FIXTURE Filed Nov.29, 1929 2 Sheets-Sheet 1 I I INVENTOR fleryairzzizflfiwfi I BY 73 M AORNEY.

May 31, 1938. B, D. BROWN AUTOMATIC CONTOUR SHAPING FIXTURE Filed Nov.29, 1929 2 Sheets-Sheet 2 ATTC N EY to grind straight lines.

Patented May 31, 1938 ,UNITD SE'TES 6 Claims.

This invention relates to profile shaping apparatus and moreparticularly to devices for grinding contours on objects in conformitywith a predetermined shape, and has special reference to apparatus forgrinding watch crystals, thin lenses of optical devices, and the like,either curved or straight in cross section.

Up to the present time, machines for grinding irregular contours, e. g.on lenses, have not been able to duplicate micrometrically the outlineof a master pattern. This necessitated either hand grinding of the lenseto fit a given frame, or stretching or otherwise altering a frame tosuit the lense. These machines have never been able Watch crystals, onthe other hand, since they must be ground to micrometrically fit a metalbezel, have hitherto been ground byhand to a master pattern. Variationin hand pressure and lack of proper means of accurate adjustment havealways resulted in a lack of micrometric precision with itsresultantscrapping of a proportion of the finished product.

The following will explain why all other machines have failed to producemicrometric similarity or proportionalityto a master pattern:-

In' order to duplicate micrometrically the irregular contour of a givenmaster pattern, the pointsof tangency, between any two given points onthe master pattern and its stop or gauge must have the same includedangle with respect to the centre of curvature of the gauge as therelative two points of tangency between the work and the cuttingdiameter have with respect to the centre of the cutting diameter. Anyeccentricity between the centre of curvature of the master-pattern,gauge and the centre of the cutting diameter will cause a change in theincluded angle relationship mentioned above with a resultantdissimilarity between the contour of the master pattern and finishedwork. As the eccentricity increases, the dissimilarity increases, until,with a master pattern stop of infinite radius, or the reverse, itreaches its extremes. Within the range of ordinary usage, thedissimilarity is not very marked to the naked eye when dealing withcontours made up of continuous curves. When, however, the contour ismade up of intersecting curves, particularly flat curves, or when thecontour is made up of straight lines, the dissimilarity is quite evidenteven to the naked eye. 7

No machine, up to the present. made-any provision for having andmaintaining, during all adjustments, I a concentric. relationshipbetween the cutting diameter and the master-patterngauge workingdiameter.

The main object of this invention is to provide a machine toduplicate'with micrometric precision the contour shapes of watchcrystals, lenses, and the like.

Further purposes of a machine made in accordance with the invention are(1) to grind irregular contours micrometrically similar to the contourof a master pattern, (2) to grind con tours made up of straight linesmicrometrically similar to the contour of a master pattern, (3) to grindeither irregular contours or straight line contours micrometricallyproportional to the master pattern, (4) to grind either irregularcontours or straight line contours either micro" metrically similar orproportional to a master pattern, with either a square or bevelled edge.

Afurther object of the present invention is to provide a machine havinga counterbalanced work-carrying head guided with respect to the abradingwheel by a former or master having the required shape.

A further feature is in the provisions of means for minutely varying thesize of the part to be ground from that of the master guide.

Another purpose is to produce a chuck or holder to grip the object,provisions also being made to centralize and properly index the objectwith respect to the master guide and the holder.

These and other important objects such as the production of accuratework by essentially automatic methods, the provision of a simple andeasily operated mechanism, and means for making fine adjustments in thegrinding operation, are accomplished by the novel and practicalconstruction, combination and arrangement of parts, hereinafterdescribed and illustrated in the accompanying drawings, forming amaterial component of this disclosure, and in which:

Figure 1 is a top plan View of an embodiment of the invention,indicating its use.

Figure 2 is a side elevational view of the same, shown as in operation.

Figure 3 is a plan view showing part of the work holding head.

Figure-3a is a portion of Figure 3 in cross section.

Figure 4 is a partial longitudinal sectionalview of the work clampingand moving device.

Referring to my automatic contour grinding fixture, in general, anadjustable clamp-holder, with a setting gauge, holds the piece to beground, the latter resting against the face ofa rotating grinding wheeL-The piece, whose contour is to be ground, is rotated against therotating grinding wheel, by means of a pivoted balanced drive whichpermits the piece to rise and fall to suit the contour and whichmaintains constant pressure between the piece to be ground and thegrinding wheel. Concentric with the piece held in the clamp-holder, is acam having a shape coincident with that to which the piece is to beground, the said cam having a tapered edge to suit the tapered face of acam gauge, the cam gauge being concentric with the grinding wheel. Byproviding endwise adjustment of either cam or cam gauge proportions ofthe finished part can be varied or compensation can be made for the wearon the grinding wheel. When the piece-is ground to size, the cam restson the cam gauge and prevents further grinding. In addition to thevariation obtainable through endwise adjustment, the size andproportions of the finished ground piece can be increased or decreasedas desired by varying the ratio between the maximum outside diameter ofthe cam gauge and the outside diameter of the grinding wheel and makingthe cam larger or smaller as desired.

As shown in the drawings the numeral l6 designates the base platform ofthe machine, from which rises a bracket equipped with a pair of spacedbearings I for a shaft l2.

A belt receiving pulley I3 is rotatably mounted on the shaft outwardlybeyond the bearing H and fixed in the outerside of the pulley hub is astud |4 adapted to act as a clutch member with reference to projectionsl5 at the inner side of a collar l6 held rigidly on the end of theshaft.

Interposed between the collar 6 and pulley hub is a compression spring|1 encircling the shaft and pressing the pulley away from the collar.

Loosely mounted on the shaft, between the pulley hub and bearing II is acollar I8 having a cam face I 9 to coact with a projection on the outerend of the bearing whereby the cam collar l8 may be forcibly pressedagainst the pulley hub to move the clutch elements into 0perativeengagement when desired by actuating a handle 20 fixed in the cam collarto extend into a position conveniently to be reached.

Fixed to the shaft |2 on both sides of the bearing II are collars 2| andalso fixed to the shaft at its end is another collar 22.

Freely mounted on the shaft between its bearing is a sleeve 23 having astem 24 preferably reduced at its outer portion 25, and between thecollars 2| and 22 is another sleeve 26 having a stem 21 reduced at 26.

Also extending from the sleeve 26, in an opposite direction is anotherstem 29 having a reduced portion 36 on which is adjustably mounted aweight 3|.

The reduced stems 2528 support a plate 32 forming part of brackets 34 inthe former of which is rotatably mounted a spindle 35 having fixed onits outer end a sprocket wheel 36 driven by a chain 31 trained over asmaller sprocket 38 fixed on the shaft |2.

On the opposite end of the spindle 35 is a spur pinion 39 meshing with agear 40' keyed on a spindle 4| rotatably journaled in a boss 42 on thebracket 34.

The above constitutes generally the carriage for supporting the patternor template and work holder hereinafter described.

A square axial passage 41 is formed through the spindle 4| to slidablyreceive a bar 48 of rectangular cross section, the outer end of the barbeing threaded into a plate 49 forming one of the jaws of the workholding clamp.

Fig. 30. indicates mechanism for relative positioning of pattern 81 andwork holder arm 48; 42 is a boss on bracket 34; screw 45 threaded intothis boss has a shoulder 44 engaging groove 43 in sleeve 4| which has asquare hole 41 in which slides the square shaft 48. Sleeve4l holdspattern 81, while shaft 48 holds one-half of work holder 49 and 13. Inthe hub of gear 46 in Figure 3a are shown two set screws, 40A, 40C,respectively, the one to the right of the figure, namely, 46A passesthrough a slot 463 in sleeve 4| and locks square shaft 48 to the hub.The set screw 46C in hub of gear 46 abuts against fiat 46D in sleeve 4|.If the screw to the left, 460, is locked against fiat 46D and the screwto the right, 40A, is loosened, shaft 48 can be moved as desired, whilesleeve 4| holding pattern 81 remains in fixed position. On the otherhand, screw 46A to the right of hub may be locked in position, whilescrew 40C to the left of hub may be loosened and operation of screw 45engaged in groove 43 will move in sleeve 4| as desired, while shaft 48remains fixed. After adjustment of screw 45, screw 46 will lock 45 inposition.

A forwardly extending boss 56 on the bracket 34 has rigidly secured init 'a spindle 5| provided with a key way and also with a flattenedportion 52 to slidably but not rotatably receive an adjustable bracket53 equipped with, a knurled set screw 54 by which the bracket may beheld firmly on the spindle.

A hollow sleeve 55 is integral with the bracket 53, its partially closedinner end acting as a guide for spindle 56 the adjacently extending endof which carries the rotatable hub of a platev 51 arranged in opposedrelation to and registration with the plate 49, the plate having anantifriction bearing on the spindle end.

Fixed on the spindle 56, within the sleeve 55, is

a limiting collar 58 pressed outwardly by a compression spring 59encircling the spindle and abutting a plug 69 screw threaded into theouter end of the sleeve, these elements being best seen in Figure 4.

The forwardly extending end of the spindle 56 is recessed to receive theentering end of a lever 6|, pivoted at 62 in a stud 63 set in thebracket 53, the lever having an extending operative handle 64.

Obviously by raising the handle the lever will act to draw the spindle56 outwardly, against the pressure of the spring 59, thus separating theplates 49-51, and. to provide means for retaining the plates whenseparated the spindle has a slot 65 having reduced edges 66 at its innerportion.

A detent pin 61 is slidably mounted transversely in the bracket plug 60to pass through the spindle slot 65 and is provided with an enlargedhead 68 engageable with the reduced portions 66 of the slot when thespindle is retracted.

The extending end of the detent pin 61 has secured to it a knurled handknob 69 and is equipped with an encircling compression spring 16,pressing the detent into a normally engaging position.

slidably but not rotatably mounted on the sleeve 55, at its innerextending portion, is the hub 1| of a cup-like guide 12 which may beraised in adjusting the work parts 15 between cushion clamp elements1314, carried by the respective plates 4951. i i E The guide 12 isnormally drawn into inoperative position by a tension spring 16extending between the cu and aipin set in the outer part of thesleeve-55; 1 a

A support bracket T21, fixed 'on'the base 10, carries. a 'spindle lii"having in- -its outer portions an annular groove 19 receptive of afl'ange'80 formedon a screw 82 provided with a knurled head 82 andthreaded into the bracket 11 in a plane below and parallel with thespindle 18 which is thereby adjusted in a'positive manner.

At the outer end of -the spindle T8 is a cam gauge 83 having-aconicalface, the smaller end being outward and in the end of the spindle i8 isan axial opening toreceiv'e a guide pin il i extending from the end ofan'arbor 86 on which is secured a grinding wheel 85.

This wheel ls'rotated at a' high rate of speed by means not shown, suchfor instance as a flexible shaft, but it is to be understood that theaxis of the arbor is 'fixed and -inexact alinement with the axis ofthe cam' gauge 83, the wheel and gauge being concentric.

Fixed to the forward end of the hollow spindle ll is a master cam,pattern or former 8'! through which the bar 48 passes, the cam beingbevelled in the opposite direction from the gauge 83 upon which itnormally rests, due to the excess weight of the elements carried by theswing bracket over the weight 31.

By reason of the bevelled contacting surfaces of the cam and gauge, thedistance between their axes may be minutely varied by operation of screw8! or 45 to a definite extent.

In operation the machine may be unclutched by the lever 2|] stoppingrotation of the spindles, and the head raised, if desired from theabrading wheel.

Thereupon the handle 64 being raised, the work clamping elements areseparated and so held if desired, while other work parts aresubstituted.

Upon pressing the knob 69, the clamps are forced against the work by thespring 59 and the work is adjusted centrally and indexed properly by aidof the cup gauge 12.

It will be understood that the cam element 8'! is shaped in exactproportionate conformity with the outline or contour that is to beimparted'to the work part and that variations in size of the latter maybe readily effected by moving the cam gauge with respect to the mastercam or vice versa.

It will be further understood that a suitable cutter (not shown) may besubstituted for the grinding wheel 85, and by providing spring means(not shown) extending from pivot arm or stem 21, sufficient pressure maybe obtained to maintain contact between the cutter and work partsagainst the resistance force of the cutter, thereby converting thedevice into a milling fixture.

If the overall range in diameter of the cutting or grinding wheel 85 isvery large, or otherwise, the gauge 83, instead of being the frustum ofa cone, can be made up of radial sections of such frustums all attachedconcentrically to the gauge axis. Under such a condition, the gaugewould be locked in position so that the required section faced themaster cam 87. The master cam may, of course, be proportionate in sizeto the desired work, instead of being the exact size, and the gaugediameter arranged to suit.

The foregoing disclosure is to be regarded as descriptive andillustrative only, and not as restrictive or limitative of theinvention, of which obviously an embodiment may be constructed includingmany modifications without departing from' -th'e general scope hereinindicatedand denoted in the ap ended claims. 1

Having thus described .my invention, what I claim as new and desire tosecure by Letters Patentjis'ra A I; In a" contour shaping machine,thecombination with apattern, and a work holder operable therewith, of ashaper, aconical gauge journaled for rotary movement in contact withwhich the pattern rolls, 'said shaper and said gauge being mountedon acommon axis, said pattern and said work holder being movable in a fixedpath relative"to said shaper and said gauge, means for rotating saidworkholderand said pattern, and means to micrometrically longitudinallyadjust said gaugealong its axis relative to said pattern to compensatefor wear of the shaper and without changing the concentricity of saidshaper and said gauge, and means for locking said gauge in adjustedposition against" longitudinal displacement.

2. In a contour shaping machine, the combination with a pattern, and awork holder operable therewith, of a shaper, a conical gauge journaledfor rotary movement in contact with which the pattern rolls, said shaperand said gauge being mounted on a common axis, a swingable framemounting said pattern and said work holder for swinging movement in afixed path relative to said shaper and said gauge, means formechanically rotating said work holder and said pattern, and means tomicrometrically longitudinally adjust said gauge along its axis relativeto said pattern to compensate for wear of the shaper and withoutchanging the concentricity of said shaper and said gauge, and means forlocking said gauge in adjusted position against longitudinaldisplacement.

3. In a contour shaping machine, the combination with a pattern, andwork holder operable therewith, of a shaper and a gauge in axialalinement, a carriage for supporting, and moving in a fixed path saidpattern and said work holder toward and from said shaper and said gauge,means for rotating said work holder and said pattern, said gauge havinga working surface of varying concentric diameters against which the saidpattern may ride, said working surface being concentric with the shapingsurface of said shaper, means to micrometrically longitudinally I adjustsaid gauge and said pattern relative to each other whereby theperipheral contour of said pattern is accurately reproduced in directproportion on a piece of work, which may be held by the work holder andshaped by the shaper, at all points of said relative adjustment, andmeans for lockingly maintaining said adjustment.

4. In a contour shaping apparatus, the combination with a pattern, and awork holder operable therewith, of a gauge against which the pattern mayride, and a shaper, said shaper and said gauge being in axial alinement,a carriage for supporting, and moving in a fixed path said pattern andsaid work holder toward and from said shaper and said gauge, means forrotating said work holder and said pattern, said gauge having a workingsurface of varying concentric diameters and having its working surfaceconcentric with the shaping surface of said shaper, means tomicrometrically vary the longitudinal relation between said gauge andsaid pattern whereby the peripheral contour of said pattern isaccurately reproduced in direct proportion on a piece of work, which maybe held by the work holder and shaped by the shaper, at all points ofsaid relative adjustment, and means for locklngly maintaining saidadjustment. 5. In a contour shaping machine, the combination of arotatable shaper, a tapered gauge, said shaper and gauge being mountedon a common axis, said gauge having a working surface of varyingconcentric diameters, the working surface of said gauge being concentricwith the shaping surface of said shaper, a unit movable in a fixed pathrelative to said shaper and said gauge, said unit having a Work holderand a pattern holder in axial alinement, meansfor rotating said workholder and said pattern holder, means to micrometrically longitudinallyadjust said'gauge to vary the limits of movement of said unit whilemaintaining the aforementioned concentricity whereby the peripheralcontour of said patternisaccurately reproduced in direct proportion on apiece of work, which maybe held by the work holder and shaped by theshaper,

at all points of said adjustment, and means for lockingly maintainingsaid adjustment.

6. In a contour shaping machine the combination with a pattern, and awork holder operable therewith, of a shaper, a conical gauge againstwhich the pattern may ride, the said shaper and said gauge being mountedon a common axis, a carriage for supporting, and moving in a fixed pathsaid pattern and said work holder toward and from said shaper and saidgauge, means for rotating said work holder and said pattern, and meansto micrometrically longitudinally adjust said gauge along its axisrelative to said-shaper andsaid pattern whereby the peripheral contourof said pattern is accurately reproduced in direct proportion on a pieceof work, which may be held by the work holder and shaped by the shaper,at all points of said relative adjustment, and means for lockinglymaintaining said adjustment.

BENJAMIN D. BROWN;

